public class Circle {
    public static final double pi=3.1415926;
    private double radius;

    public Circle(double radius) {
        this.radius = radius;
    }

    public Circle() {
    }

    public static double getPi() {
        return pi;
    }

    public double getRadius() {
        return radius;
    }

    public void setRadius(double radius) {
        this.radius = radius;
    }

    public double area() {
        return radius*radius*pi;
    }

    public static void main(String[] args) {
        Circle c = new Circle(5);
        System.out.println(c.area());
    }
}
